Children who are African American, Hispanic, rural, living with single mothers, or living in central cities are less likely than other children to have access to computers and the Internet. This "digital divide" has been widely documented, yet we know little about its effect on children's health and cognitive, social, and emotional development. The proposed study will determine whether computer use affects various child outcomes including obesity, depression, cognitive skill, behavioral problems, and substance use. The study will reveal the extent to which lack of computer access causes disadvantaged children to fall behind their advantaged counterparts in dimensions that are enhanced by computer use (e.g., cognitive skill), and the extent to which they gain relative to their privileged counterparts in areas where computer use has potentially harmful effects (e.g., obesity and anti-social behavior). The study will use data from the Child and Young Adult Surveys conducted as part of the 1979 National Longitudinal Survey of Youth to estimate a variety of outcome models in which measures of computer use are among the controls. A production function framework will be used to describe how computer use and other inputs contributed by children, families, schools, and neighborhoods combine to "produce" selected outcomes of interest. To identify the causal effect of computer use on each outcome (as opposed to simply identifying correlations), instrumental variables estimation will be used; instruments will include computer prices and high-speed Internet access measured at the county-year level, taken from external various surveys and trade publications. The effect of computer use on each outcome will be allowed to vary by location of use (home versus school), type of use (e.g., games versus communication versus educational pursuits), intensity of use, and age of use. Racial and ethnic differences in children's health and development are a primary policy concern, as are differences associated with gender, family structure, and geographic location. The study will determine how computer use affects child health and development across these racial, ethnic, and socioeconomic groups. Child health and development will be measured by obesity, scores on a depression scale, and scores on a behavioral problems index, cognitive test scores, and substance use. [unreadable] [unreadable] [unreadable]